install dragonfly on RAID

[Ji]

Hi all,

I am new to DragonFly and have some problem installing it.
Your help is desired.

My machine is with PowerEdge Expanable RAID controller.
I first tried Automatic Installation by logining with "installer",
but it failed saying "cannot find suitable disk to install"; then I
tried manual installation,
but it seems still unable to find any disks. (I typed in "fdisk", it feedbacks
"cannot open any disk: Device not configured.")
I checked handbook and mail archives and could not find the answer.
Could someone give me a hand?

Thank you very much.
ji